Abstract
The Puerto Rican parrot (Amazona vittata) is a small (28 cm, 250-350 g) amazon parrot with emerald green plumage that provides perfect camouflage for the bird in the lush tropical foliage of its rain forest home. In flight its brilliant blue wing feathers appear jewel-like as the parrot manuevers over the forest canopy. The parrot's raucous calls once filled the forests of the West Indian island of Puerto Rico. Tragically, it is now one of the many Amazona parrot species in dire jeopardy and is listed as endangered along with the red-necked (A. arausiaca), red-tailed (A. brasiliensis), St. Vincent (A. guildingii), imperial (A. imperialis), and St. Lucia (A. versicolor) parrots (King 1978). In fact, most of the Caribbean parrots are in peril and many, such as the Cuban macaw (Ara tricolor) and the Puerto Rican parakeet (Aratinga maugei), are already extinct (see Clark 1905a, 1905b, 1905c; Greenway 1958).
Parrot's Decline
Although the Puerto Rican parrot was found throughout Puerto Rico when Columbus discovered the island in 1493, the population steadily declined with European man's colonization of the island. Much of the original forest was cleared to make room for farms and grazing land for domestic animals. In the early 1900's there were still several thousand parrots, but a drastic decrease in the parrot's range had, occurred; by about 1940 the species was found only in the Luquillo Forest of eastern Puerto Rico where it exists today in the 11,330 hectare (28,000 acre) Caribbean National Forest.
The U.S. Forest Service recognized the Puerto Rican parrots' vulnerability in the rnid- l 940's and began programs to protect the bird and its habitat. However, nothing had been done to understand the species' ecology or reasons for its decline and little was done for the next 20 years. Despite the Forest Service's efforts, people continued to harvest the young birds for pets. The Service, not realizing its importance, even encouraged the removal of the parrots' favorite nesting tree, the palo colorado (Cyril/a racemif!ora), then considered a weed species. A study conducted by biologists of the Commonwealth of Puerto Rico Department of Agriculture in the
early 1950's revealed that the parrot population had declined from the estimated 2,000 in the 1930's (Wadsworth 1949) to about 200 birds (Figure 1) and the species was experiencing extremely low reproductive success resulting from a number of factors (Rodriguez-Vidal 1959).
Research
The first full-time parrot biologist was hired in 1968 by the U.S. Fish and Wildlife Service's Endangered Wildlife Research Program and the U.S. Forest Service, with financial incentive from the World Wildlife Fund. The precipitous decline of the parrot was further verified when the Service biologist found fewer than 15 percent of the population (24 of 2,000 parrots) recorded only 14 years before. The possibility for the species' survival looked extremely poor and a crash captive breeding program appeared essential to save the species. In captivity the parrots would be provided security against such natural disasters as tropical storms and disease that might wipe out the remnant Luquillo population.
The potential for captive propagation of the Puerto Rican parrot appeared to be good because of the species' behavioral characteristics and nutritional requirements, and the successful captive propagation of other Amazona species (about 60% of the species have been bred in captivity; Nichols 1978, Noegel 1979). Captive propagation has been a useful tool in the recovery of other species in the U.S. Fish and Wildlife Service's Endangered Wildlife Research Program (e.g., masked bobwhite, Co/inus virginianus ridgwayi; whooping crane, Grus americana; and Aleutian Canada goose, Branta canadensis /eucopareia), but none of these other efforts have been as closely integrated into the management program to save the species as has been for the Puerto Rican parrot. The Endangered Wildlife Research Program began a propagation effort for this species at the Patuxent Wildlife Research Center in 1970 with the construction of facilities and testing of them with the more abundant Hispaniolan parrot (A. ventralis). The use of a surrogate (captive population of a closelyrelated, nonendangered species) is part of
all captive studies at Patuxent. Treatments, techniques, and risks of any kind are tested with the surrogate species before using them on the rarer species (Erickson 1968).
Luquillo Aviary
In 1971 the Puerto Rico Zoo at Mayaguez donated the first 2 Puerto Rican parrots to the Patuxent program. These birds had been taken as nestlings from the Luquillo Forest in 1956, but the zoo did not attempt serious captive propagation until the late l 960's. In 1972, 1 of 2 wild birds recently caught in the Luquillo Forest for transfer to Patuxent died while in the U.S. Department of Agriculture Animal and Plant Health Inspection Station quarantine in Florida. The survivor was added to the Patuxent flock after an additional quarantine at Patuxent. An outbreak of Asiatic Newcastle disease in Puerto Rico dictated that these and all other parrots transferred from Puerto Rico would undergo a similar rigorous and potentially hazardous quarantine. The decision to establish a 2nd aviary in Puerto Rico was made shortly after the loss of the quarantined bird, as such risks wen .. unacceptable, and a captive facility was needed to support other aspects of the field studies in Puerto Rico. The Luquillo aviary would furnish a place to care for eggs, and to rehabilitate sick and injured birds from the wild, as well as a site for captive breeding. Construction of the Luquillo aviary was completed in late 1973. Facility design, medical care, nutrition, and other management programs were provided by Patuxent and successful psittacine aviculturists.
In 1973, 5 Puerto Rican parrots were taken as eggs or chicks from the forest and placed in the new aviary. Since 1973 all additions from the wild to the Luquillo aviary have been either as eggs or nestlings. Meanwhile, captive propagation studies continued at Patuxent; in 1973, the first Hispaniolan chick was hatched and reared there. However, it was decided that the parrot captive propagation effort should be centralized at the field aviary, so by the end of 1978, the captive Puerto Rican and Hispaniolan parrot populations were transferred from Patuxent to the Luquillo aviary.
During the development of the captive program, the team of Fish and Wildlife Service and Forest Service biologists and technicians found a myriad of problems threatening the parrots' survival in the wild. It was immediately evident that the parrot is an extremely difficult species to study in the field, living in dense tropical forests and being exceedingly wary and inconspicuous.